Ten unusual facts about calories

Calories are at the heart of most modern weight-loss diets: we all know that to lose weight, we need to eat fewer calories than we expend.

But even though the word “calories” is familiar to any dieter, how much do you really know about them? Here are ten facts, some of which you’ve probably never heard before:

1. The word “calorie” came into general use in English in the 1880s, according to the Oxford English Dictionary. The first example of “calorie” being used in relation to food rather than heat energy in general is this:

2. The definition of a calorie is “the amount of energy needed to raise the temperature of 1 gram of water by 1°C”.

3. In nutrition, what we talk of as “calories” are really kilocalories – enough energy to raise the temperature of a kilogram of water by 1°C. (This is why the metric unit is the kilojoule.)

4. The first diet book to advocate calorie counting and to offer lists of calories was Dr Lulu Hunt Peters’ Diet and Health With Key to the Calories. The term was new to her readers, and would have been unknown a couple of generations before. She told them that:

Hereafter you are going to eat calories of food. Instead of saying one slice of bread, or a piece of pie, you will say 100 Calories of bread, 350 Calories of pie.

5. The average deep fried mars bar contains almost 1,000 calories – that could be most of your daily allowance, if you’re a small female office dieter…

7. Eating a high-calorie diet when pregnant is linked to giving birth to boys rather than girls. (The rise in low-calorie diets in the developed world is seen as one possible reason for the increasing number of female babies being born compared to male babies.)

8. There are no calories in tea or coffee (just in the milk and sugar that you add…)

10. New York restaurants are now legally obliged to display calorie counts on menus … and in the UK, government ministers are calling for similar legislation.

Want to know more about calories? Check out the Dieting Basics ebook for full information on how many calories you should be eating, how to burn more calories than you take in, and how to calculate the calories in any portion of food.